Optical add-drop multiplexer



FIG. 1 is a perspective view of an optical add-drop multiplexer showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front elevation view thereof;

FIG. 5 is a right side view thereof, a left side view thereof being a mirror image; and,

FIG. 6 is a rear elevation view thereof. 

The ornamental design for an optical add-drop multiplexer, as shown and described. 